<?php
class Student
{

    private $surname;
    private $first_name;
    private $emails;
    private $grades;
    private $status; 


    function __construct($surname, $first_name, $status)
    {
        $this->surname = $surname;
        $this->first_name = $first_name;
        $this->status = $status; 
        $this->emails = array();
        $this->grades = array();
    }


    function add_email($which, $address)
    {
        $this->emails[$which] = $address;
    }


    function add_grade($grade)
    {
        $this->grades[] = $grade;
    }


    function average()
    {
        $total = 0;
        foreach ($this->grades as $value) {
            $total += $value;
        }
        return $total / count($this->grades);
    }


    function toString()
    {
        $result = $this->first_name . ' ' . $this->surname;
        $result .= ' (' . $this->average() . ') ';
        $result .= $this->status . "\n"; 
        foreach ($this->emails as $which => $what) {
            $result .= "\n";
            $result .= $which . ': ' . $what . "\n";
        }
        return '<pre>' . $result . '</pre>';
    }
}
?>